From 7851d682ba1fccc50472a0813039bb508f865549 Mon Sep 17 00:00:00 2001 From: phga Date: Fri, 23 Jul 2021 23:55:15 +0200 Subject: [PATCH] update: discussion wpm + ter done --- chap4/methodology.tex | 3 +- chap6/discussion.tex | 99 ++++++++++++++++++++++++++++++++++++++++++- glossary.tex | 1 + thesis.tex | 15 +++++++ 4 files changed, 115 insertions(+), 3 deletions(-) diff --git a/chap4/methodology.tex b/chap4/methodology.tex index 8d4bc83..9013d2b 100644 --- a/chap4/methodology.tex +++ b/chap4/methodology.tex @@ -20,8 +20,7 @@ hand was able to apply to distinct keys in different locations. We then created the design for the adjusted keyboard based on those measurements. Lastly, an experiment with twenty-four participants was conducted, where we compared the performance and user satisfaction while using four different keyboards, -including our adjusted keyboard, to values obtained with the participant's own -keyboards. +including our adjusted keyboard. \subsection{Preliminary Telephone Interview} \label{sec:telephone_interview} diff --git a/chap6/discussion.tex b/chap6/discussion.tex index fc373b4..621689b 100644 --- a/chap6/discussion.tex +++ b/chap6/discussion.tex @@ -1,2 +1,99 @@ \section{Discussion} -\label{sec:label} +\label{sec:discussion} +In the following sections, we reiterate on our findings presented in the last +section and try to derive answers regarding our seven hypotheses and research +question \textit{``Does an adjusted actuation force per key have a positive + impact on efficiency and overall satisfaction while using a mechanical + keyboard?''}. + +\subsection{Impact of Actuation Force on Typing Speed} +\label{sec:dis_speed} + +Our main experiment yielded, that there are differences in typing speed for both +metrics related to transcribed text we measured―namely \glsfirst{WPM} and +\glsfirst{AdjWPM}. Especially the keyboard with the lowest uniform actuation +force of 35 g―\textit{Nyx}―performed worse than all other keyboards. In terms of +\gls{WPM}, \textit{Nyx (35 g)} was on average 4.1\% slower than \textit{Athena + (80 g)} and \textit{Aphrodite (50 g)} and 4.8\% slower than the adjusted +keyboard \textit{Hera (35 - 60 g)}. Similarly, for \gls{AdjWPM}, \textit{Nyx} +was 4.3\% slower than \textit{Athena} and \textit{Aphrodite} and 4.9\% slower +than \textit{Hera}. The 4\% to 5\% difference in \gls{WPM} and \gls{AdjWPM} in +our sample account for approximately 2 words per minute. When extrapolated with +the mean daily keyboard usage of 6.69 hours reported by our participants, this +difference would be as big as 803 words, which when put into perspective, is +equivalent to roughly two full pages of only written content (11pt font +size). Although, this specific example would assume constant typing for 6.69 +hours, it is still a useful estimate of the loss in productivity under normal +working conditions over the course of several days. These differences in +\gls{WPM} and \gls{AdjWPM} could be explained by the higher error rates and +thereby the loss of ``typing flow'' we discuss in the next section. \gls{KSPS} +reflects the raw input speed by including backspaces and previously deleted +characters. The reason we included \gls{KSPS} in our analysis was to reveal +possible differences in the physical speed participants type on a keyboard and +not to further asses speed in the sense of productivity. We could not find any +statistically significant differences in \gls{KSPS} but saw a trend, indicating +that subjects typed a bit slower (< 3\%) on \textit{Athena (80 g)} compared to +\textit{Aphrodite (50 g)} and \textit{Hera (35 - 60 g)}. With the differences in +metrics that are commonly used to measure typing speed more closely related to +productivity (\gls{WPM}, \gls{AdjWPM}) and the trends that indicate a slight +difference in operating speed, we can accept our hypothesis that solely a +difference in actuation force has an impact on typing speed. + +\begin{phga_hyp}[\checkmark] + Actuation force has an impact on typing speed (efficiency - speed). +\end{phga_hyp} + +% During our telephone interviews 76\% of respondents would have preferred a +% keyboard with lighter actuation force. + +% Our study tried to present the participant with a typing scenario that is as +% close to a typical text input situation as possible, by allowing but not +% enforcing the correction of erroneous input. + +\subsection{Impact of Actuation Force on Error Rate} +\label{sec:dis_error} + +As already briefly mentioned in Section \ref{sec:dis_speed}, measured error +rates like \glsfirst{UER}, \glsfirst{CER} and \glsfirst{TER} differed especially +between \textit{Nyx (35 g)} and the other test keyboards. The statistical +analyses further revealed, that \textit{Athena}, the keyboard with the highest +actuation force of 80 g, produced on average 1\% less \gls{TER} than +\textit{Hera (35 - 60 g)} and \textit{Aphrodite (50 g)} and 3\% less than +\textit{Nyx (35g)}. Furthermore, \textit{Hera} and \textit{Aphrodite} both had a +2\% lower \gls{TER} than \textit{Nyx}. Additionally to the quantitative results, +fourteen of the twenty-four participants also reported, that \textit{Nyx's} +light actuation force was the reason for many accidental key presses. It further +stood out, that as shown in Figure \ref{fig:max_opc_ter}, \textit{Athena} was +the most accurate keyboard for 58\% of participants and also more accurate than +keyboard \textit{Own} for eleven of the subjects. This concludes, that a higher +actuation force has a positive impact on error rate. + +\begin{phga_hyp}[\checkmark] + Higher key actuation force decreases typing errors compared to lower key + actuation force (efficiency - error rate). +\end{phga_hyp} + +\textbf{Impact of \gls{TER} on \gls{WPM}} + +The higher error rates and the possibility to correct erroneous input could have +also been a factor that led to lower \textit{WPM}. To evaluate the likelihood of +this additional relation, we conducted a \gls{LRT} of fixed effects for our +linear mixed-effects model with two random effects (participant and first/second +typing test), fixed effect \gls{TER} and response variable \gls{WPM}. The +results of the \gls{LRT} ($\chi^2(1)$ = 110.44, p = 0.00000000000000022) +suggest, that the \gls{TER} indeed had an impact on \gls{WPM}. This could have +been, because every time an error was made, almost all participants decided to +correct it right away. With a higher error rate, this obviously leads to many +short interruptions and an increased number of characters that are not taken +into account when computing the \gls{WPM} metric. + + +\subsection{Impact of Actuation Force on Satisfaction} +\label{sec:dis_sati} + +\subsection{Impact of Actuation Force on Muscle Activity} +\label{sec:dis_emg} + +\subsection{Impact of an Adjusted Keyboard on Typing Speed, Error Rate and + Satisfaction} +\label{sec:dis_hera} \ No newline at end of file diff --git a/glossary.tex b/glossary.tex index 96280b4..e8f9f2e 100644 --- a/glossary.tex +++ b/glossary.tex @@ -43,6 +43,7 @@ \newacronym{OPC}{OPC}{percentage of keyboard ``Own''} \newacronym{SP}{SP}{starting point} \newacronym{EP}{EP}{end point} +\newacronym{LRT}{LRT}{Likelihood Ratio Test} diff --git a/thesis.tex b/thesis.tex index 43c9f96..e3c05e5 100644 --- a/thesis.tex +++ b/thesis.tex @@ -22,6 +22,7 @@ openright]{scrartcl} \usepackage[font=footnotesize]{caption} \usepackage[outputdir=auto]{minted} \usepackage[framemethod=tikz]{mdframed} +\usepackage{amssymb} \BeforeBeginEnvironment{minted}{\begin{mdframed}} \AfterEndEnvironment{minted}{\end{mdframed}} @@ -115,12 +116,26 @@ citecolor=red, skipbelow = 20pt, linecolor=thi_blue, frametitlebackgroundcolor=thi_blue!8, + backgroundcolor=thi_blue!8, linewidth=1.9pt, leftline=false, rightline=false, bottomline=false, } \mdtheorem[style=phga_sum]{phga_sum}{Relevance for this Thesis} +\mdfdefinestyle{phga_hyp}{ + skipabove = 20pt, + skipbelow = 20pt, + linecolor=thi_blue, + frametitlebackgroundcolor=thi_blue!8, + backgroundcolor=thi_blue!8, + backgroud=thi_blue!8, + linewidth=1.9pt, + leftline=false, + rightline=false, + bottomline=false, +} +\mdtheorem[style=phga_hyp]{phga_hyp}{Hypothesis} % ----Glossar------------------------------------------------------------------------- \usepackage[toc,acronym,nonumberlist,nogroupskip]{glossaries}